Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

Depress the horn switch.

Does the horn operate?

Go to Step 3

Go to Step 5

1. Install a scan tool.
2. Turn ON the ignition, with the engine OFF.
3. With a scan tool, command the body control module (BCM) Horn Output ON and OFF.

Does the horn operate?

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 4

4

Test the BCM portion of the horn relay control circuit for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 21

Go to Step 11

5

1. Turn OFF the ignition.
2. Disconnect the horn relay.
3. Connect a test lamp between the battery positive voltage circuit of the horn relay coil and a good ground.

Does the test lamp illuminate?

Go to Step 6

Go to Step 14

1. Connect a test lamp between the battery positive voltage circuit of the horn relay coil and the horn relay control circuit.
2. Depress and hold the horn switch.

Does the test lamp illuminate?

Go to Step 7

Go to Step 15

7

Connect a test lamp between the battery positive voltage circuit of the horn relay switch and a good ground.

Does the test lamp illuminate?

Go to Step 8

Go to Step 16

Momentarily connect a 15-amp fused jumper wire between the battery positive voltage circuit of the horn relay switch and the horn control circuit.

Do the horns operate?

Go to Step 12

Go to Step 9

1. Reconnect the horn relay.
2. Disconnect either horn connector.
3. Connect a test lamp between the horn control circuit and a good ground.
4. Depress and hold the horn switch.

Does the test lamp illuminate?

Go to Step 10

Go to Step 17

1. Connect a test lamp between the horn control circuit and the horn ground circuit.
2. Depress and hold the horn switch.

Does the test lamp illuminate?

Go to Step 13

Go to Step 18

Inspect for poor connections at the harness connector of the BCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 21

Go to Step 19

Inspect for poor connections at the horn relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 21

Go to Step 20

13

Important: A resistance as low as 0.5ohms could cause operating problems with the horn.

Repair the high resistance in the horn control circuit or the horn ground circuit. Refer to Circuit Testing and Wiring Repairs .

Did you complete the repair?

Go to Step 21

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Repair the open or high resistance in the battery positive voltage circuit of the horn relay coil. Refer to Circuit Testing and Wiring Repairs .

Did you complete the repair?

Go to Step 21

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15

Important: The horn switch is part of the inflatable restraint steering wheel module. Refer to Inflatable Restraint Steering Wheel Module Replacement .

1. To disable the SIR system, refer to SIR Disabling and Enabling .
2. Repair the open or short to voltage in the horn relay control circuit. Refer to Circuit Testing and Wiring Repairs .

Did you complete the repair?

Go to Step 21

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Repair the open or high resistance in the battery positive voltage circuit of the horn relay switch. Refer to Circuit Testing and Wiring Repairs .

Did you complete the repair?

Go to Step 21

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Repair the open or high resistance in the horn control circuit. Refer to Circuit Testing and Wiring Repairs .

Did you complete the repair?

Go to Step 21

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Repair the open or high resistance in the horn ground circuit. Refer to Circuit Testing and Wiring Repairs .

Did you complete the repair?

Go to Step 21

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Replace the BCM. Refer to Control Module References .

Did you complete the repair?

Go to Step 21

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Replace the horn relay.

Did you complete the replacement?

Go to Step 21

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Operate the horn.

Does the horn operate properly?

System OK

Go to Step 1